Cut bottoms off leeks, cut in half lengthwise, rinsing well under
running water, making sure to rinse off dirt hiding between layers.
Slice thinly. Sauté leeks/onions and garlic in margarine until soft. Add
potatoes and water, bring to boil and reduce to medium. Toss in pepper,
bay leaves, dill and tarragon (if using). Cook until potatoes are soft
(about 20-30 minutes). Remove bay leaf and discard. Transfer half or
more of the potatoes from pot and mash with potato masher, mixing with
1-2 cups nut milk to puree, then return them to broth. Salt to taste.
Serve with crusty bread.